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Journal articles on the topic 'Minimum chi-square estimation'
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Baker, Frank B. "Item parameter estimation via minimum logit chi-square." British Journal of Mathematical and Statistical Psychology 40, no. 1 (1987): 50–60. http://dx.doi.org/10.1111/j.2044-8317.1987.tb00867.x.
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Vuong, Quang H., and Weiren Wang. "Minimum chi-square estimation and tests for model selection." Journal of Econometrics 56, no. 1-2 (1993): 141–68. http://dx.doi.org/10.1016/0304-4076(93)90104-d.
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Baker, Frank B. "Comparison of minimum logit chi-square and Bayesian item parameter estimation." British Journal of Mathematical and Statistical Psychology 44, no. 2 (1991): 299–313. http://dx.doi.org/10.1111/j.2044-8317.1991.tb00963.x.
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Barbiero, Alessandro. "Least-squares and minimum chi-square estimation in a discrete Weibull model." Communications in Statistics - Simulation and Computation 46, no. 10 (2017): 8028–48. http://dx.doi.org/10.1080/03610918.2016.1263733.
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Wosniok, Werner, and Rainer Haeckel. "A new indirect estimation of reference intervals: truncated minimum chi-square (TMC) approach." Clinical Chemistry and Laboratory Medicine (CCLM) 57, no. 12 (2019): 1933–47. http://dx.doi.org/10.1515/cclm-2018-1341.
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Abstract All known direct and indirect approaches for the estimation of reference intervals (RIs) have difficulties in processing very skewed data with a high percentage of values at or below the detection limit. A new model for the indirect estimation of RIs is proposed, which can be applied even to extremely skewed data distributions with a relatively high percentage of data at or below the detection limit. Furthermore, it fits better to some simulated data files than other indirect methods. The approach starts with a quantile-quantile plot providing preliminary estimates for the parameters (λ, μ, σ) of the assumed power normal distribution. These are iteratively refined by a truncated minimum chi-square (TMC) estimation. The finally estimated parameters are used to calculate the 95% reference interval. Confidence intervals for the interval limits are calculated by the asymptotic formula for quantiles, and tolerance limits are determined via bootstrapping. If age intervals are given, the procedure is applied per age interval and a spline function describes the age dependency of the reference limits by a continuous function. The approach can be performed in the statistical package R and on the Excel platform.
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Hühn, M. "Maximum likelihood vs. minimum chi-square-A general comparison with applications to the estimation of recombination fractions in two-point linkage analysis." Genome 43, no. 5 (2000): 853–56. http://dx.doi.org/10.1139/g00-054.
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Some relationships between the estimates of recombination fraction in two-point linkage analysis obtained by maximum likelihood, minimum chi-square, and general least squares are derived. These theoretical results are based on an approximation for the multinomial distribution. Applications (theoretical and experimental) with RFLP (restriction fragment length polymorphism) markers for a segregating F2 population are given. The minimum chi-square estimate is slightly larger than the maximum likelihood estimate. For applications, however, both estimates must be considered to be approximately equal. The least squares estimates are slightly different (larger or smaller) from these estimates.Key words: linkage analysis, recombination fraction, maximum likelihood, minimum chi-square, general least squares.
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Clark, Stephen, and David Weir. "Class-Based Probability Estimation Using a Semantic Hierarchy." Computational Linguistics 28, no. 2 (2002): 187–206. http://dx.doi.org/10.1162/089120102760173643.
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This article concerns the estimation of a particular kind of probability, namely, the probability of a noun sense appearing as a particular argument of a predicate. In order to overcome the accompanying sparse-data problem, the proposal here is to define the probabilities in terms of senses from a semantic hierarchy and exploit the fact that the senses can be grouped into classes consisting of semantically similar senses. There is a particular focus on the problem of how to determine a suitable class for a given sense, or, alternatively, how to determine a suitable level of generalization in the hierarchy. A procedure is developed that uses a chi-square test to determine a suitable level of generalization. In order to test the performance of the estimation method, a pseudo-disambiguation task is used, together with two alternative estimation methods. Each method uses a different generalization procedure; the first alternative uses the minimum description length principle, and the second uses Resnik's measure of selectional preference. In addition, the performance of our method is investigated using both the standard Pearson chi-square statistic and the log-likelihood chi-square statistic.
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Wani, Fehim J. "On Methods of Estimation for Generalized Logarithmic Series Distribution and Its Application to Counts of Red Mites on Apple Leaves." Indian Journal of Pure & Applied Biosciences 9, no. 3 (2021): 151–55. http://dx.doi.org/10.18782/2582-2845.8689.
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The Generalized Logarithmic Series Distribution (GLSD) adds an extra parameter to the usual logarithmic series distribution and was introduced by Jain and Gupta (1973). This distribution has found applications in various fields. The estimation of parameters of generalized logarithmic series distribution was studied by the methods of maximum likelihood, moments, minimum chi square and weighted discrepancies. The GLSD was fitted to counts of red mites on apple leaves and it was observed that all the estimation techniques perform well in estimating the parameters of generalized logarithmic series distribution but with varying degree of non-significance.
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Kim, Seock-ho, Frank B. Baker, and Michael J. Subkoviak. "The 1/kn rules in the minimum logit chi-square estimation procedure when small samples are used." British Journal of Mathematical and Statistical Psychology 42, no. 1 (1989): 113–26. http://dx.doi.org/10.1111/j.2044-8317.1989.tb01119.x.
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Fu, Yun-Xin, and Ranajit Chakraborty. "Simultaneous Estimation of All the Parameters of a Stepwise Mutation Model." Genetics 150, no. 1 (1998): 487–97. http://dx.doi.org/10.1093/genetics/150.1.487.
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Abstract Minisatellite and microsatellite are short tandemly repetitive sequences dispersed in eukaryotic genomes, many of which are highly polymorphic due to copy number variation of the repeats. Because mutation changes copy numbers of the repeat sequences in a generalized stepwise fashion, stepwise mutation models are widely used for studying the dynamics of these loci. We propose a minimum chi-square (MCS) method for simultaneous estimation of all the parameters in a stepwise mutation model and the ancestral allelic type of a sample. The MCS estimator requires knowing the mean number of alleles of a certain size in a sample, which can be estimated using Monte Carlo samples generated by a coalescent algorithm. The method is applied to samples of seven (CA)n repeat loci from eight human populations and one chimpanzee population. The estimated values of parameters suggest that there is a general tendency for microsatellite alleles to expand in size, because (1) each mutation has a slight tendency to cause size increase and (2) the mean size increase is larger than the mean size decrease for a mutation. Our estimates also suggest that most of these CA-repeat loci evolve according to multistep mutation models rather than single-step mutation models. We also introduced several quantities for measuring the quality of the estimation of ancestral allelic type, and it appears that the majority of the estimated ancestral allelic types are reasonably accurate. Implications of our analysis and potential extensions of the method are discussed.
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Besnard, Guillaume, Catherine Breton, Philippe Baradat, Bouchaib Khadari, and André Bervillé. "Cultivar Identification in Olive Based on RAPD Markers." Journal of the American Society for Horticultural Science 126, no. 6 (2001): 668–75. http://dx.doi.org/10.21273/jashs.126.6.668.
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One hundred and thirteen olive (Olea europaea L.) accessions were characterized using randomly amplified polymorphic DNA (RAPD) markers. Forty-five polymorphic RAPD markers were obtained enabling us to distinguish 102 different RAPD profiles. The approximate estimation of the probability of obtaining the same RAPD profile for two different trees was between 6.75 × 10-5 and 4.82 × 10-14. A dendrogram was constructed using Ward's minimum variance algorithm based on chi-square distances. This led to a more clear-cut classification of profiles than the classical approach of unweighted pair group method with arithmetic average. Twenty-four clusters of RAPD profiles were shown in Ward's dendrogram. Reliability of the dendrogram structure was checked using variance analysis. RAPD data exhibited an acceptable resolving power for cultivar identification. A combination of three primers was proposed for rapid molecular identification of cultivars in collections and in nurseries.
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Bunch, David S., and Richard R. Batsell. "A Monté Carlo Comparison of Estimators for the Multinomial Logit Model." Journal of Marketing Research 26, no. 1 (1989): 56–68. http://dx.doi.org/10.1177/002224378902600105.
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Marketing researchers use the multinomial logit (MNL) model to analyze discrete choice, and estimate parameters either by maximum likelihood (ML) or minimum logit chi square (MLCS). Some controversy persists, however, over which is better. Review articles in marketing recommend ML over MLCS, but the statistics literature suggests that MLCS should be preferred. No studies have directly compared the performance of ML and MLCS in a marketing context. The authors assess the relative performance of ML, MLCS, and three other candidate estimators for MNL marketing applications involving repeated-measures datasets collected by means of multiple-subset designs. In contrast to most previous findings in the statistics literature, the results strongly support the use of ML. ML is found to outperform the other estimators on a variety of point estimation, predictive accuracy, and statistical inference criteria and ML test statistics are found to have asymptotic behavior for datasets involving relatively few replications.
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Shamshad, Bushra, and Junaid Sagheer Siddiqui. "Testing Procedure for Item Response Probabilities of 2Class Latent Model." Mehran University Research Journal of Engineering and Technology 39, no. 3 (2020): 657–67. http://dx.doi.org/10.22581/muet1982.2003.20.
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This paper presents Hotelling T2 as a procedure for the testing of significance difference between the item response probabilities (ωij′s) of classes in a Latent Class Model (LCM). Parametric bootstrap technique is used in order to generate samples for ωij′s. These samples are based on the estimated parameters of 2-class latent model. The estimation of parameters in either situation is done using the Expectation Maximization (EM) algorithm through Maximum likelihood method. The hypothesis under consideration is whether the response probabilities (ωij′s) are equal against each item in both the classes. { H0 : ωi1 = ωi2. against H1 : =ωi1 ≠ ωi2}. If the test exhibits significant difference between response probabilities in both classes, it will be a clear indication of a presence of latent variable. We consider both training and testing data sets to develop the test. In order to apply Hotelling T2 test the basic assumptions of normality and homogeneity of variance are also checked. Chi-square goodness of fit test is used for assessing normal distribution to be good fitted on the hypothesized (bootstrap samples) based on 2-class latent model parameters for each data and Bartlett test to check heterogeneity of variances in ωij′s. Moreover, our procedure produces a minimum standard error of estimates as compared to those obtained through the package in R.Gui environment
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Patnaik, Manasi, Tejaswini M, Sudhanshu Kumar Rath, and Shaik Afrah Naaz. "Role of admission cardiotocography and amniotic fluid index on perinatal outcome in low risk pregnancy at term." International Journal of Reproduction, Contraception, Obstetrics and Gynecology 10, no. 4 (2021): 1591. http://dx.doi.org/10.18203/2320-1770.ijrcog20211142.
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Background: Fetal surveillance even in normal or low risk pregnancy is essential to ensure safe parturition with minimum intervention. Cardiotocography (CTG) and clinical estimation of amniotic fluid volume (AFV) measured as amniotic fluid index (AFI) are two tests that are easily available in the labor room and can be used to identify fetal well-being. Our study aimed to evaluate role of admission cardiotocography (CTG) and amniotic fluid index (AFI) on perinatal outcome in low risk pregnancy at term.Methods: The study was conducted as a prospective observational study. All low risk pregnant women at term admitted to the labor ward in early or established labour between September 2018 and August 2020 were included in the study. They underwent admission CTG and AFI assessment using ultrasonography. All parameters including CTG changes, mode of delivery, AFI, presence of meconium, APGAR score at 1 and 5 mins, need for admission in neonatal ICU and perinatal mortality were recorded. Quantitative data was compared using chi square test.Results: A total of 180 patients were included in the study. Majority of the women belonged to the age group of 30-35 years. Abnormal CTG showing fetal distress was seen in 105 (58.33%) cases. Non-reactive CTG was significantly associated with meconium stained liqour, requirement for LSCS, still birth, fetal distress, APGAR <7 at 1 and 5min and NICU admission (p<0.001). The association of low AFI with non-reactive CTG had statistically significant impact on perinatal outcomes like low birth weight, requirement for LSCS, fetal distress, APGAR <7 at 1 and 5 mins and NICU admissions.Conclusions: Admission CTG is a simple non-invasive test that can serve as a screening tool in low risk obstetric population to detect fetal distress already present or likely to develop and prevent unnecessary delay in intervention. Thus, it may help in preventing fetal morbidity and mortality.
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Robin, Jean-Marc, and Richard J. Smith. "TESTS OF RANK." Econometric Theory 16, no. 2 (2000): 151–75. http://dx.doi.org/10.1017/s0266466600162012.
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This paper considers tests for the rank of a matrix for which a root-T consistent estimator is available. However, in contrast to tests associated with the minimum chi-square and asymptotic least squares principles, the estimator's asymptotic variance matrix is not required to be either full or of known rank. Test statistics based on certain estimated characteristic roots are proposed whose limiting distributions are a weighted sum of independent chi-squared variables. These weights may be simply estimated, yielding convenient estimators for the limiting distributions of the proposed statistics. A sequential testing procedure is presented that yields a consistent estimator for the rank of a matrix. A simulation experiment is conducted comparing the characteristic root statistics advocated in this paper with statistics based on the Wald and asymptotic least squares principles.
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Yokoyama, Yasuhisa, Masahiko Gosho, Takahiro Suzuki, et al. "Analysis of the Prevalence and Risk Factors of Adult Neutropenia in a Large Cohort in Japan." Blood 128, no. 22 (2016): 4738. http://dx.doi.org/10.1182/blood.v128.22.4738.4738.
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Abstract Background: The prevalence of neutropenia is estimated to be 0.5% to 25% based on the definition of neutrophil count less than 1,500 /μL. The high variety mostly depends on the race. Most of the estimation have been based on the values obtained from one measurement of neutrophil count. The prevalence of "chronic" neutropenia is largely unknown, particularly in adults, with only a few small epidemiological studies of adult chronic neutropenia being found. Here we analyzed the medical-check data from over 30,000 Japanese adults, and report the prevalence and characteristics of neutropenia in Japanese adults referring to chronic cases. Methods: Data of medical-checks including neutrophil count from 2010 to 2014 were collected. The entire cohort included 33,255 adults. Neutropenia was defined as neutrophil count less than 1,500 /μL. Anemia was defined as hemoglobin level less than 13 g/dL in men and 12 g/dL in women, and thrombocytopenia as platelet count less than 100,000 /μL. Data of past histories and comorbidities were based on the self-report by the participants. When simple neutropenia (not necessarily chronic) was analyzed, the minimum neutrophil count was used for those who received more than one medical-checks, and other data at the time of the minimum neutrophil count were adopted. For the statistical analysis for comparison of subjects with and without neutropenia, Student's t-test or Wilcoxon's rank sum test were used for continuous variables, and chi-square test was used for categorical variables. Univariate and multivariate regression analyses were performed for testing the effect of the candidate factors on the neutrophil count. For the analysis of the risk factors of neutropenia, multivariate logistic regression analysis was used. For the analysis of chronic neutropenia, only those who received at least 2 medical-checks with measurement of neutrophil count were included. Those who showed neutropenia at least twice were defined as having chronic neutropenia. Results: After exclusion of the cases with past histories of hematological malignancies, 33,201 cases were included. Among them, 1,391 (4.18%) cases had neutropenia. Frequencies of collagen diseases, hypothyroidism, and under-treatment hyperthyroidism were higher in the neutropenic group than the non-neutropenic group. When the subjects with these diseases were excluded, 1,348 (4.12%) out of 32,695 cases had neutropenia. Among them, frequencies of anemia and thrombocytopenia in the neutropenic group were higher than in the non-neutropenic group (18.7% vs 6.2%, and 0.7% and 0.1%, respectively, p < 0.001). In order to analyze isolated neutropenic cases, the subjects with anemia and/or thrombocytopenia were further excluded from the cohort. As the result, 28,615 cases were analyzed. Among them, 1,083 (3.78%) cases were diagnosed to have neutropenia, in which 1,025 (94.6%) cases had mild neutropenia (1,000 - 1,499 /μL) and 58 (5.4%) had moderate neutropenia (500 - 999 /μL). There were no cases of severe neutropenia (< 500 /μL). The neutropenic group showed older age (52.2 vs 50.2 years old), female predominance (64.2% vs 37.1%), lower bone mass index (BMI) (21.5 vs 23.4), lower smoking habit (23.3% vs 46.5%), lower drinking habit (30.8% vs 38.3%) (p < 0.001 for all). Diabetes mellitus (3.0% vs 4.9%, p = 0.005), hypertension (10.6% vs 15.7%, p < 0.001), and hyperuricemia (1.7% vs 3.3%, p = 0.003) were less frequent, and pollen allergy (6.3% vs 4.2%, p < 0.001) and viral hepatitis (1.1% vs 0.3%, p < 0.001) were more frequent in the neutropenic group. In multivariate regression analysis, female, drinking habit, pollen allergy, and viral hepatitis were associated with decrease in neutrophil count, whereas higher BMI and smoking habit with increase in neutrophil count. Risk factors of neutropenia were female with adjusted odds ratio (OR) 2.18 (p < 0.001), drinking habit (OR 1.31, p < 0.001), pollen allergy (OR 1.32, p = 0.034), and viral hepatitis (OR 3.98, p < 0.001). Higher BMI and smoking habit were negative factors of neutropenia (OR 0.40 and 0.52, respectively, p < 0.001).Among the 18,279 subjects who received at least 2 medical checks with measurement of neutrophil count, the number of chronic neutropenia was 294 (1.61%). Conclusion: The prevalence of isolated neutropenia in Japanese cohort was 3.78%, and chronic neutropenia was seen in 1.61%. Risk factors of neutropenia were female, drinking habit, pollen allergy, and viral hepatitis. Disclosures No relevant conflicts of interest to declare.
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Wang, Jixin, Shuang You, Yuqian Wu, Yingshuang Zhang, and Shibo Bin. "A Method of Selecting the Block Size of BMM for Estimating Extreme Loads in Engineering Vehicles." Mathematical Problems in Engineering 2016 (2016): 1–9. http://dx.doi.org/10.1155/2016/6372197.
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Extreme loads have a significant effect on the fatigue damage of components. The block maximum method (BMM) is widely used to estimate extreme values in various fields. Selecting a reasonable block size for BMM is crucial to ensure that proper extreme values are extracted to get extreme sample to estimate extreme values. Aiming at this issue, this study proposed a comprehensive evaluation approach based on multiple-criteria decision making (MCDM) method to select a proper block size. A wheel loader with six sections in one operating cycle was illustrated as an example. First, spading sections of each operating cycle were extracted and connected as extreme loads often occur at that section. Then extreme sample was obtained by BMM for fitting the generalized extreme value (GEV) distribution. Kolmogorov-Smirnov (K-S) test, Pearson’s Chi-Square (χ2) test, and average deviation in Probability Distribution Function (PDF) are selected as the fitting test. The comprehensive weights are calculated by the maximum entropy principle. Finally, the optimal block size corresponding to the minimum comprehensive evaluation indicator is obtained and the result exhibited a good fitting effect. The proposed method can also be flexibly used in various situations to select a block size.
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Baumhauer, Judith, Michael Anderson, Charles Saltzman, et al. "Generalizability and Validation of PROMIS Scores to Predict Surgical Success in Foot and Ankle Patients." Foot & Ankle Orthopaedics 2, no. 3 (2017): 2473011417S0000. http://dx.doi.org/10.1177/2473011417s000026.
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Category: Patient Reported Outcomes Introduction/Purpose: Patient-reported outcomes are advancing clinical care by improving patient satisfaction and engagement. A recent publication reported preoperative PROMIS scores to be highly predictive in selecting patients who would and would not benefit from foot and ankle (F/A) surgery. Although this publication used the data from 5 fellowship trained foot and ankle surgeons at one institution, the generalizability to other patient populations and geographic areas is unknown. This validation study assesses the pre-operative PROMIS physical function (PF) and pain interference (PI) t-scores as a predictor of post-operative success from a separate geographic area. Methods: Prospective consecutive patient visits to a multi-surgeon tertiary F/A clinic were obtained between 1/2014-11/2016 resulting in 18,565 unique visits and 1,408 new patients. Patients undergoing elective operative intervention for F/A were identified by ICD-9/10; CPT code. PROMIS PF and PI were assessed at initial and follow-up visits (minimum 6 months, mean 7.8 months). Two-way ANOVA was used to determine differences in PROMIS PF and PI from pre to post surgery with age and gender as co- variates. The distributive method of estimating a minimal clinical important difference (MCID) was used. Receiver operator curve (ROC) analysis was used to determine cut offs for achieving and failing to achieve MCID. To determine the validity of previously published cut offs, 1) they were compared to cut offs for this data set and 2) the percentage of patients achieving and failing to achieve MCID based on previous cut offs were evaluated using a chi-square analysis. Results: There were significant improvements in PROMIS PF scores (mean=6.0; sd=11.6; p<0.01) and PI scores (mean=-7.0; sd=8.4; p<0.01). The AUC for PROMIS PF (0.77) was significant (p < 0.01) and the cut offs for achieving MCID (current data = <23.8 versus previous study= <29.7) and failing to achieve MCID (current data=>41.1 versus previous study=>42) were comparable (Figure 1). Of the patients identified as unlikely to achieve MCID, a significant proportion (88.9%) failed to achieve an MCID ((Chi square=4.7; p=0.03). Of the patients identified as likely to achieve MCID, a significant proportion (84.2%) achieved MCID ((Chi square=17.8; p<0.01). This validates the prior preoperative PROMIS PF thresholds for patients undergoing F/A surgery who will and will not demonstrate MCID improvement in PROMIS PF. The AUC for PROMIS PI was not significant. Conclusion: PROMIS PF cut offs from published data were successful in classifying patients who would improve in PF with surgery from a different geographic area and academic institution with a broad unique array of surgical procedures, diagnoses, and a diverse patient population. This study provides validation evidence to support using the PROMIS PF as a potential tool for surgical selection to help identify patients who would benefit from surgery as well as those who would not. This can allow for appropriate utilization of healthcare dollars and manpower resources to benefit our patients.
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Jafar, Muh Alfian, Syarifuddin Rauf, and Dasril Daud. "Profile of Minimal and Non-Minimal Change Nephrotic Syndrome in Children: A Cross-Sectional Study." Green Medical Journal 2, no. 2 (2020): 39–48. http://dx.doi.org/10.33096/gmj.v2i2.51.
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Introduction: Idiopathic nephrotic syndrome (INS) is the most common kidney disease in children. Histopathological features classify the disease into minimal change nephrotic syndrome (MCNS) and non-minimal change nephrotic syndrome (NMCNS). Clinical and laboratory characteristics are considered to be useful in estimating the underlying pathological changes. This study aimed to assess the spectrum of clinical and laboratory profiles in children suffering from MCNS and NMCNS.
 Methods: This was a cross-sectional study using medical records of patients hospitalized at Dr. Wahidin Sudirohusodo Central General Hospital and Hasanuddin University Teaching Hospital from January 2016 to August 2018. Subjects were classified into MCNS and NMCNS groups and evaluated for age, sex, hypertension, degree of edema, degree of hematuria, proteinuria level, cholesterol level, albumin level, urea level, and creatinine level. Data were analyzed by using chi-square, fisher's exact test Mann Whitney analysis, multivariate by logistic multiple regression analysis, and diagnostic test.
 Results: Of the 36 subjects enrolled, 10 (27.8%) had MCNS, and 26 (72.2%) had NMCNS. Bivariate analysis showed significant differences in hypertension (p=0.020; OR=12.3; 95% CI 1.35-111.61) and hematuria (p=0.018; OR=7.7 ; 95% CI 1.52-39.75). Multivariate analysis indicated that only hematuria is a significant predictor (p=0.014; OR=7.778; 95% CI 1.522 – 39.754). The diagnostic test of NMCNS showed hematuria sensitivity at 77% and specificity at 70% with a positive predictive value of 87% and a negative predictive value of 46%.
 Conclusion: Our study showed that hematuria is a sensitive predictor of NMCNS.
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Gadag, Raveendra P., Puneeth S. Nayak, and Tejaswini J. "Clinical Asssessment of Sensorineural Hearing Loss among Diabetes Mellitus Patients." Bengal Journal of Otolaryngology and Head Neck Surgery 28, no. 2 (2020): 112–19. http://dx.doi.org/10.47210/bjohns.2020.v28i2.297.
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Background: Hearing impairment is known to hamper the quality of life among patients, especially among diabetics due to the association of neuropathy with diabetes. However, the prevalence and degree of the SNHL depends upon different factors, such as age, gender, disease duration of DM, family history and glycemic status of the patients. Therefore, this study aimed to assess the association of SNHL with DM duration and familial DM and gender preponderance among SNHL–DM patients.
 Methods: Total 140 patients with DM were assessed for hearing impairment using Rinne, Weber and Absolute Bone Conduction Tests along with pure tone audiometry. Patients’ glycaemic status was determined by estimating fasting blood glucose (FBG) and post prandial blood glucose (PPBG) levels. Independent t-test, chi-square, ANOVA and Pearson’s correlation tests along with linear regression model were used to find association and correlation using R software.
 Results: Out of 140 patients, 60 were suffering from SNHL and majority were suffering from bilateral minimal hearing loss. SNHL was significantly associated with family history, age, duration of DM, FBG and PPBG levels were(Pvalues:1.79E08, 4.41E-06 and 0.02), however, significant correlated with duration of DM, FBS and PPBG level (r value:0.14–0.41).Furthermore, significant SNHL at 500 and 8000Hz was observed in the present study (Pvalue:0.002).
 Conclusion: A conclusive proof was drawn that family history of DM serve as a valuable variable in assessing the SNHL among DM patients.
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Clauser, Paola, Matthias Dietzel, Michael Weber, Clemens G. Kaiser, and Pascal AT Baltzer. "Motion artifacts, lesion type, and parenchymal enhancement in breast MRI: what does really influence diagnostic accuracy?" Acta Radiologica 60, no. 1 (2018): 19–27. http://dx.doi.org/10.1177/0284185118770918.
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Background Motion artifacts can reduce image quality of breast magnetic resonance imaging (MRI). There is a lack of data regarding their effect on diagnostic estimates. Purpose To evaluate factors that potentially influence readers’ diagnostic estimates in breast MRI: motion artifacts; amount of fibroglandular tissue; background parenchymal enhancement; lesion size; and lesion type. Material and Methods This Institutional Review Board-approved, retrospective, cross-sectional, single-center study included 320 patients (mean age = 55.1 years) with 334 histologically verified breast lesions (139 benign, 195 malignant) who underwent breast MRI. Two expert breast radiologists evaluated the images considering: motion artifacts (1 = minimal to 4 = marked); fibroglandular tissue (BI-RADS FGT); background parenchymal enhancement (BI-RADS BPE); lesion size; lesion type; and BI-RADS score. Univariate (Chi-square) and multivariate (Generalized Estimation Equations [GEE]) statistics were used to identify factors influencing sensitivity, specificity, and accuracy. Results Lesions were: 230 mass (68.9%) and 59 non-mass (17.7%), no foci. Forty-five lesions (13.5%) did not enhance in MRI but were suspicious or unclear in conventional imaging. Sensitivity, specificity, and accuracy were 93.8%, 83.4%, and 89.8% for Reader 1 and 95.4%, 87.8%, and 91.9% for Reader 2. Lower sensitivity was observed in case of increased motion artifacts ( P = 0.007), non-mass lesions ( P < 0.001), and small lesions ≤ 10 mm ( P < 0.021). No further factors (e.g. BPE, FGT) significantly influenced diagnostic estimates. At multivariate analysis, lesion type and size were retained as independent factors influencing the diagnostic performance ( P < 0.033). Conclusion Motion artifacts can impair lesion characterization with breast MRI, but lesion type and small size have the strongest influence on diagnostic estimates.
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Osei, Christian Kwaku, Edward Nketiah-Amponsah, and Monica Puoma Lambon-Quayefio. "Household wealth and maternal health: evidence from Ghana." International Journal of Social Economics 48, no. 1 (2020): 63–83. http://dx.doi.org/10.1108/ijse-03-2020-0153.
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PurposeIn 2016, the World Health Organization (WHO) revised upwards the recommended contacts for antenatal care (ANC) by expectant mothers with a health provider from a minimum of four to eight over the pregnancy period. Although Ghana is yet to adopt the new recommendation, some women choose to adhere to the new protocol because of its enormous health benefits to the expecting mother and the unborn child. As part of ANC, family planning services are also provided to ensure child spacing and birth control. To reduce health costs, government introduced the free maternal health policy, Community-based Health Planning Services, Livelihood Empowerment Against Poverty and established the Northern Development Authority to increase access to healthcare and also create wealth. Given these interventions, the study hypothesizes that household wealth would not have a significant influence on antenatal visits and modern contraceptive use. Therefore, this paper aims to examine whether household wealth would play any significant role on the new minimum contacts proxied by antenatal visits and also on the use of modern contraceptives as a family planning counselling tool during ANC visits. The study further examines a possible heterogeneity effect of paternal characteristic on maternal health service utilization.Design/methodology/approachThe study used data from the most recent Ghana Demographic and Health Survey (GDHS, 2014). Both bivariate and multivariate analyses were used to investigate the effects of household wealth on the number of antenatal visits and modern contraceptive use. The bivariate analysis employed the use of chi-square test whiles, the multivariate analysis involved estimations using logistic regressions.FindingsThe findings show that household wealth would play a critical role given the revised WHO minimum ANC contacts by expectant mothers. Household wealth exerts a positive and significant effect on ANC for all wealth quintiles for women who attended at least eight ANC visits, but was insignificant for the poorer and middle quintiles of those who attended four to seven visits. Wealth, however, had an insignificant relationship with modern contraceptive use. Generally, education, age, birth order, media exposure as well as geographical locations had a significant influence on both ANC visits and modern contraceptive use. The study further revealed a heterogeneous effect on ANC attendance. In particular, despite the relatively poor conditions, women in rural areas whose partners/husbands have attained a minimum of secondary education are about twice more likely to attend 4–7 antenatal visits compared to their counterparts whose husbands/partners are without education. Hence, a holistic health education, which includes husbands/partners in the rural areas as well as strengthening interventions that improve livelihoods, is crucial.Originality/valueHealth guidelines are constantly reviewed, and government policies must adapt accordingly. This paper looks at the significant role household wealth still plays on modern contraceptive use and ANC visits, given the revised WHO minimum ANC contacts and uniquely underscores the influence of paternal characteristics on the utilization of these maternal health services.
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Kiss, Csongor, Bettina Kárai, Katalin Gyurina, et al. "Staining Pattern of Leukemic Lymphoblasts for Coagulation Factor XIII Subunit a Correlates with Clinical Outcome and B-Other Genotype in Childhood Acute Lymphoblastic Leukemia." Blood 132, Supplement 1 (2018): 5285. http://dx.doi.org/10.1182/blood-2018-99-118203.
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Abstract Introduction: Subunit A of blood coagulation factor XIII (FXIIIA) may be expressed in leukemic B-cell precursor (BCP) lymphoblasts in addition to platelets, megakaryocytes, monocytes and macrophages (Kiss F. et al Thromb Haemost 2006;96:172-82.). In a retrospective single-center cohort of children with acute lymphoblastic leukemia (ALL) treated with the BFM ALL-IC 2002 protocol, expression of FXIIIA was correlated with statistically significant survival advantage (Kárai B et al. Pathol Oncol Res 2018; 24:345-52.). Our aim was to investigate the impact of FXIIIA expression pattern on EFS and its correlation with known clinical and genetic prognostic factors in a multi-center pilot study within the frames of the BFM ALL-IC 2009 clinical trial (EuDract: 2010-019722-13). Patients and Methods: We examined 317 children with BCP-ALL between 2011 and 2018 at institutions in Poland (n=188), Hungary (n=116), and Slovakia (n=13). Patients with Down-syndrome, t(9;22), and infants (<1 year) were excluded. Immunophenotype and minimal residual disease (MRD) were determined by flow cytometry (FC). Cytogenetic analysis and fluorescence in situ hybridization were performed according to standard methods. DNA extracted from bone marrow samples was processed for SALSA multiplex ligation-dependent probe amplification P335-B2 ALL-IKZF1 probe mix (MRC-Holland, Amsterdam, The Netherlands) analysis according to manufacturer's instructions. Statistical analysis: Survival analysis was carried out by the Kaplan-Meier estimator. More than 2 groups were analyzed by the Kruskal-Wallis test. Dunn's multiple comparison was applied as post host test. Dichotomous categorical variables were compared by Chi square test and logistic regression to analyze multiple variables. P<0.05 was considered significant. Results: We observed 3 different patterns of FXIIIA expression in leukemic lymphoblasts: negative pattern (<20%), moderate positive expression (20-79%), and strong positive pattern (>80%). Evaluation of FC histograms of the moderate positive pattern showed that FXIIIA expression increased continuously which excluded the existence of distinct FXIIIA negative and FXIIIA positive subpopulations within the moderate positive expression group (Fig.1). In contrast to the previous single-center retrospective cohort, EFS of patients with FXIIIA positive BCP-ALL was not significantly different from that of patients of FXIIIA negative BCP-ALL (Fig.2A). However, a significant EFS advantage of patients with moderate FXIIIA positivity was demonstrated when compared with patients with FXIIIA negative BCP-ALL (p=0.019), and with patients with FXIIIA strong positive BCP-ALL (p=0.001) (Fig.2B). The 3 different FXIIIA expression patterns did not correlate significantly with either risk stratification according to BFM ALL-IC 2009 or FC MRD categories. Intermediate genetic risk categories (low hyperdiploidy, t(1;19), and "B-other") were significantly more prevalent (p=0.042) among patients with FXIIIA negative BCP-ALL than among patients with strong FXIIIA positive BCP-ALL. The "B-other" subgroup was also significantly more prevalent (p=0.022) among patients of the above 2 groups (Table 1). Distribution of the "B-other" genetic group and the prednisone response differed significantly between the FXIIIA positive and negative groups. Intermediate genetic risk group is mostly made up of patients assigned to the "B-other" group explaining the significant difference between the FXIIIA positive and negative groups, in terms that FXIIIA negative patients had 50% lower chance of facing low instead of intermediate genetic risk compared to FXIIIA positive patients. The multivariate logistic regression analysis confirmed the association between the FXIIIA characteristics and the intermediate genetic risk group. This association persisted after adjusting for categorical variables, i.e. gender, age, WBC, and BFM ALL-IC 2009 stratification (Table 2). High risk copy number alterations were detected in 4/7 samples of the FXIIIA negative group and in 1/17 of the FXIIIA positive group. Conclusions: FXIIIA expression status of leukemic lymphoblasts can easily be determined by FC. Patients with FXIIIA negative lymphoblasts should be further investigated with sophisticated and more expensive genetic and molecular methods. Grant sponsor: OTKA K108885. Disclosures No relevant conflicts of interest to declare.
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Peng, Hanxiang, and Anton Schick. "Efficient estimation of a linear functional of a bivariate distribution with equal, but unknown, marginals: The minimum chi-square approach." Statistics & Decisions 22, no. 4/2004 (2004). http://dx.doi.org/10.1524/stnd.22.4.301.64311.
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Jeutho Gouajio, Marinette, Pascalin Tiam Kapen, and David Yemele. "Comparison of numerical methods in estimating Weibull parameters to install a sustainable wind farm in mount Bamboutos, Cameroon." International Journal of Energy Sector Management ahead-of-print, ahead-of-print (2021). http://dx.doi.org/10.1108/ijesm-02-2020-0019.
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Purpose The purpose of this paper is to evaluate the wind energy potential of Mount Bamboutos in Cameroon by comparing nine numerical methods in determining Weibull parameters for the installation of a sustainable wind farm. Design/methodology/approach By using statistical analysis, the analysis of shape and scale parameters, the estimation of the available wind power density and wind direction frequency distributions, the objective of this paper is to compare nine numerical methods in estimating Weibull parameters for the installation of a sustainable wind farm in Mount Bamboutos, Cameroon. Findings The results suggested that the minimum and maximum values of the standard deviation occurred in the months of May and November 2016, respectively. The graphical method appeared to be the most effective method with the maximum value of variance and minimum values of chi-square and RMSE. The scale factor parameter values indicated that Mount Bamboutos hills were a potential site for electricity generation. The analysis of wind power density showed that it reached the maximum and minimum values in February and September, respectively. The wind direction frequency distributions showed that the prevailing wind directions were North-East. Originality/value The wind energy potential of Mount Bamboutos in Cameroon was performed by using nine numerical methods. Therefore, it could be effective to have a prediction model for the wind speed profile. The analysis of wind power density showed that it reached the maximum and minimum values in February and September, respectively. The wind direction frequency distributions showed that the prevailing wind directions were North-East.
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Haeckel, Rainer, Werner Wosniok, Antje Torge, Ralf Junker, and _. _. "Reference limits of high-sensitive cardiac troponin T indirectly estimated by a new approach applying data mining. A special example for measurands with a relatively high percentage of values at or below the detection limit." LaboratoriumsMedizin, November 25, 2020. http://dx.doi.org/10.1515/labmed-2020-0063.
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AbstractA new model for the indirect estimation of reference limits (RLs) has been proposed recently and was coined TMC approach (truncated minimum chi-square estimation) which can be performed with R statistic. A spline function is applied to the RLs to get a continuous function if age is graphically presented vs. the RLs avoiding artificial “jumps” between different age groups. Most indirect models assume a power normal distribution and fail if this assumption is not fulfilled as e.g. if a relatively high percentage of measured values is below the detection limit and the data are distributed extremely skewed. This problem is handled by the TMC model. High-sensitive cardiac troponin T (hs cTnT) was chosen as an example. The hs cTnT concentration in serum or plasma is well accepted as a valuable marker in the diagnosis of acute myocardial infarction. Currently, the 99th percentile derived from a “healthy” subpopulation is the decision limit recommended by consensus groups. However, this decision limit is questioned by several authors for many reasons. In the present report, the 97.5th and the 99th percentile limits were reinvestigated by the TMC model with different subpopulations stratified according to age and sex and were finally compared to presently recommended decision limits. In summary, the generally recommended 99th percentile as a fixed decision limit should be reconsidered. It is suggested to apply more specific reference limits stratified for age and sex instead of a fixed decision limit.
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Jin, Biao, Shanshan Chen, Dongjun Li, Yuechen Wang, and Elhadi Takka. "Performance analysis of SBAS ephemeris corrections and integrity algorithms in China region." Satellite Navigation 2, no. 1 (2021). http://dx.doi.org/10.1186/s43020-021-00045-z.
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AbstractSatellite Based Augmentation Systems (SBASs) improve the positioning accuracy and integrity by broadcasting to the civil aviation community the corrections and integrity parameters. A snapshot algorithm based on the minimum variance estimation is investigated in this study to calculate the satellite clock and orbit corrections. A chi-square test is performed on the remaining errors in the corrected ephemeris to guarantee the integrity. User Differential Range Error (UDRE) and scaling matrix contained in Message Type 28 are derived using the covariance information based on the assumption that one of the reference stations failed. A software package is developed and applied in the real data collected at 26 stations. International GNSS (Global Navigation Satellite System) Service (IGS) precise clock and orbit products are taken as the references to assess the accuracy of corrections. For both Global Positioning System (GPS) and BeiDou Navigation Satellite System (BDS), the range accuracy of 0.10 m can be achieved with the employment of the derived corrections. No obvious performance difference between GPS and BDS is found. UDREs for all visible satellites are generated with the maximum index of 12 and minimum index of 3. The geometric range differences calculated with IGS precise products and broadcast ephemeris are employed to assess the integrity of UDRE. It is found that the UDRE is able to bound the residuals with 99.9% confidence which meet the requirement of aviation users. With ionospheric delay corrected by Global Ionosphere Map (GIM), the positioning accuracy of 0.98 m with GPS corrections and 0.80 m with multi-constellation augmentation can be achieved which indicates a significant improvement of GPS standalone results.
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Sivarajah, Ponniah. "Vegetable Farmer’s Awareness and Perception of Pesticides on the Environment and Health in Eastern Sri Lanka." Asian Journal of Research in Agriculture and Forestry, June 19, 2019, 1–7. http://dx.doi.org/10.9734/ajraf/2019/v3i330041.
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In Sri Lanka excessive use of pesticides in paddy and vegetable farming has caused much concern in terms of its impact on the environment and humans. A study was done in Eastern Sri Lanka to find out vegetable farmer’s awareness of hazard levels of pesticides, perception of pesticide impact on the environment and their health, and awareness about different methods of pest control among farmers. A multi-staged random sample of 96 vegetable farmers in five Agrarian Service Center ranges in the Eastern Province of Sri Lanka was studied, during October to November 2017, using a structured questionnaire. Frequencies estimation and Chi Square tests were done to find relationships. The results indicated that the degree of awareness on the hazardous levels of pesticides was minimal, but their perceptions on the impacts of the pesticides on the environment, humans, animals and on food items sold was high among the vegetable farmers. There was a significant spatial variation in knowledge on hazardous level of pesticides used in vegetable production. Significant differences existed between areas studied on the perception of farmers of the impact of pesticides on humans, animals, food and environment. Most of the farmers were aware about crop rotation, chemical control and manual control methods to get rid of pests. Only a low percentage of farmers were aware about biological control, cultural control and seed treatment to curtail pest attack. There were significant spatial differences in farmers’ awareness on available pest control methods. Policy makers and institutions intervening to regulate pesticides usage need to adopt multiple strategies to create awareness on the impact of pesticides on humans and the environment, through designing policies to enhance farm extension services and to encourage adoption of alternative methods of pest control.
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Thompson, Matthew, Beverly Green, Kelly Ehrlich, et al. "Abstract 50: Acceptability And Adherence To Home, Kiosk, Office Blood Pressure Measurement Compared To 24- Hour Ambulatory Monitoring In Primary Care." Hypertension 78, Suppl_1 (2021). http://dx.doi.org/10.1161/hyp.78.suppl_1.50.
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Introduction: Despite recommendations to use out of office blood pressure (BP) to confirm diagnosis of hypertension, there is little robust evidence on the acceptability of different methods for confirming hypertension. Most evaluations have involved small observational studies and have not compared measurement methods. The Blood Pressure Checks for Diagnosing Hypertension trial (BP-CHECK) trial compared the acceptability and adherence of clinic, home, kiosk and 24-hour ambulatory monitoring (ABPM) among adults with elevated BP who had not been diagnosed with hypertension. Methods: Adults presenting to Kaiser Permanente Washington primary care clinics with elevated BP but who did not have a hypertension diagnosis, were randomized to one of three arms: office, home and kiosk. ABPM was also conducted on all participants. Acceptability of each method to patients was measured using a validated questionnaire to calculate an overall score. Differences in mean acceptability by randomization arms and ABPM were calculated using linear regression models and Generalized Estimating Equations. Adherence was calculated as the proportion of participants completing their BP testing protocols and compared using chi-square tests. Results: A total of 510 individuals were randomized, with mean age 59 years, 80% white, 51% male, with mean BP of 150/88. The overall acceptability score was highest (i.e. most acceptable) for home (mean 6.2, SD 0.7) and lowest (i.e. least acceptable) for ABPM (mean 5.0, SD 1.0). Scores were intermediate for clinic (5.5, SD 1.1) and kiosk (5.4, SD 1.0) groups. Acceptability was significantly higher for all three intervention arms compared to ABPM. Adherence to the minimum number of BP readings pre-specified in the study protocol was higher for home (90.6%) and clinic (87.2%) groups than for the kiosk group (67.9%). Conclusions: Home BP measurement was the most acceptable method for diagnosing hypertension followed by measurement in the clinic or at kiosks, with ABPM the least acceptable, due to its discomfort, disturbance to sleep and to everyday activities. Although ABPM is considered the gold standard for confirming elevated BP, patients find home BP more acceptable.